Fungicidal trifluorophenyl-triazolopyrimidines

ABSTRACT

The novel compounds of formula I: (R1, R2 and Hal are defined in the specification) show selective fungicidal activity. The new compounds are processed with carriers and adjuvants to form fungicidal compositions.

This application claims priority from copending provisional application(s) Ser. No. 60/099711 filed on Sep. 10, 1998.

BACKGROUND OF THE INVENTION

This invention relates to certain triazolopyrimidine compounds, a process for their preparation, compositions containing such compounds, a method for combating a fungus at a locus comprising treating the locus with such compounds, and their use as fungicides.

EP-A-0071792 claims compounds of the formula ##STR2## in which R¹ represents alkyl, halogen, alkoxy, cyano, cycloalkyl, aryl, aryloxy, arylthio, aralkyl, arylthio, arylalkyl, arylalkyloxy or arylalkylthio each optionally substituted by halogen or alkoxy; or (R¹)_(n) represents a benzene, indane or tetrahydronaphthalene ring fused with the phenyl ring, aromatic moieties in the above groups being optionally substituted by alkyl, alkoxy, halogen or cyano; n is 1 or 2; R² and R³ are each hydrogen, alkyl or aryl, A represents a nitrogen atom or a CR⁴ group, and R⁴ is as R² but can also be halogen, cyano or alkoxycarbonyl or together with R³ can form an alkylene chain containing up to two double bonds. The compounds are said to be active against various phytopathogenic fungi, especially those of the phycomycete class. However evidence of fungicidal activity is only provided for these compounds against Plasmo-para viticola, a member of the oomycete class of fungi.

U.S. Pat. No. 5,593,996 embraces compounds of the formula ##STR3## in which R¹ represents an optionally substituted alkyl, alkenyl, alkadienyl, cycloalkyl, bicycloalkyl or heterocyclyl group; R² represents a hydrogen atom or an alkyl group; or R¹ and R² together with the interjacent nitrogen atom represent an optionally substituted heterocyclic ring; R³ represents an optionally substituted aryl group; and R⁴ represents a hydrogen or halogen atom or a group --NR⁵ R⁶ where R⁵ represents a hydrogen atom or an amino, alkyl, cycloalkyl or bicycloalkyl group and R⁶ represents a hydrogen atom or an alkyl group. Thus, compounds in which R³ is a trifluorophenyl group are generally covered by this patent application. These compounds are said to be active against fungi which are members of the ascomycetes class such as Venturia inaequalis and of the hyphomycetes class such as Altemaria solani and Botrytis cinerea. However, there is no single compound disclosed in which R³ is a 2,3,6-trifluorophenyl group.

SUMMARY OF THE INVENTION

The present invention provides a compound of formula I ##STR4## in which R¹ and R² each independently represent a hydrogen atom or an optionally substituted alkyl, alkenyl, alkynyl, alkadienyl, haloalkyl, aryl, heteroaryl, cycloalkyl, bicycloalkyl or heterocyclyl group, or

R¹ and R² together with the interjacent nitrogen atom represent an optionally substituted heterocyclic or heterobicyclic ring, and

Hal represents a halogen atom;

the new compounds show an excellent fungicidal activity in various crops.

It is an object of the present invention to provide novel fungicidal compounds.

It is also an object of the invention to provide methods for controlling an undesired fungus by contacting said plants with a fungicidally effective amount of the new compounds.

It is another object of the invention to provide selective fungicidal compositions containing the new compounds as active ingredients.

These and other objects and features of the invention will be more apparent from the detailed description set forth hereinbelow, and from the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It has surprisingly been found that the compounds of formula I ##STR5## in which R¹, R² and Hal have the meaning given above for formula I show an excellent fungicidal activity against a broad range of fungi.

In general terms, unless otherwise stated, as used herein the term halogen atom may denote a bromine, iodine, chlorine or fluorine atom, and is especially a bromine, chlorine or fluorine atom, in particular a chlorine atom.

Hal represents preferably a fluorine, chlorine, bromine or iodine atom, in particular a chlorine atom.

Optionally substituted moieties may be unsubstituted or have from one up to the maximal possible number of substituents. Typically, 0 to 2 substituents are present.

In general terms, unless otherwise stated herein, the terms alkyl, alkenyl, alkynyl, alkadienyl as used herein with respect to a radical or moiety refer to a straight or branched chain radical or moiety. As a rule, such radicals have up to 10, in particular up to 6 carbon atoms. Suitably an alkyl moiety has from 1 to 6 carbon atoms. Suitably an alkenyl moiety has from 2 to 6 carbon atoms. A preferred alkenyl moiety is allyl, or especially a 2-methylallyl group.

Unless otherwise stated herein, the term aryl, as used herein with respect to a radical or moiety refers to an aryl group having 6, 10 or 14 carbon atoms, preferably 6 or 10 carbon atoms, in particular phenyl, optionally substituted by one or more halogen atoms, nitro, cyano, alkyl, preferably C₁₋₆ alkyl, alkoxy, preferably C₁₋₆ alkoxy. Heteroaryl refers to an aryl moiety in which at least one atom in the aryl ring is nitrogen, oxygen or sulfur.

The term cycloalkyl, as used herein with respect to a radical or moiety refers to a cycloalkyl group having 3 to 8 carbon atoms, preferably 5 to 7 carbon atoms, in particular cyclohexyl being optionally substituted by one or more halogen atoms, nitro, cyano, alkyl, preferably C₁₋₆ alkyl, alkoxy, preferably C₁₋₆ alkoxy.

The term bicycloalkyl, as used herein with respect to a radical or moiety refers to a bicycloalkyl group having 5 to 10 carbon atoms, preferably 6 to 9 carbon atoms, in particular a bicyclo[2.2.1]heptanyl or bicyclo[2.2.2]octanyl group being optionally substituted by one or more halogen atoms, nitro, cyano, alkyl, preferably C₁₋₆ alkyl, alkoxy, preferably C₁₋₆ alkoxy.

The term heterocyclyl, as used herein with respect to a radical or moiety refers to a saturated heterocyclyl group having 5 or 6 ring atoms selected from carbon, nitrogen, oxygen and sulphur, at least one of which being nitrogen, oxygen or sulphur being optionally substituted by one or more halogen atoms, nitro, cyano, alkyl, preferably C₁₋₆ alkyl, alkoxy, preferably C₁₋₆ alkoxy, in particular pyrrolodinyl, pyrrazolidin, piperidinyl, piperazinyl, morpholin-4-yl or thiomorpholin4-yl.

The invention especially relates to compounds of the general formula I in which any alkyl part of the groups R¹ or R², which may be straight chained or branched, contains up to 10 carbon atoms, preferably up to 9 carbon atoms, more preferably up to 6 carbon atoms, any alkenyl or alkynyl part of the substituents R¹ or R² contains up to 10 carbon atoms, preferably up to 9 carbon atoms, more preferably up to 6 carbon atoms, any cycloalkyl part of the substituents R¹ or R² contains from 3 to 10 carbon atoms, preferably from 3 to 8 carbon atoms, more preferably from 3 to 6 carbon atoms, and any aryl part of the substituents R¹ or R² contains 6, 10 or 14 carbon atoms, preferably 6 or 10 carbon atoms, and in which each optionally substituted group independently is substituted by one or more halogen atoms or nitro, cyano, hydroxy, alkyl, preferably C₁₋₆ alkyl, cycloalkyl, preferably C₃₋₆ cycloalkyl, cycloalkenyl, preferably C₃₋₆ cycloalkenyl, haloalkyl, preferably C₁₋₆ haloalkyl, halocycloalkyl, preferably C₃₋₆ halocycloalkyl, alkoxy, preferably C₁₋₆ alkoxy, haloalkoxy, preferably C₁₋₆ haloalkoxy, trialkylsilyl, preferably tri-C₁₋₆ alkylsilyl, phenyl, halo- or dihalo-phenyl or pyridyl groups. Any alkyl, alkenyl or alkynyl group may be linear or branched. A 4- to 6- membered heterocyclic group may be any heterocyclic group with 4 to 6 ring atoms, interrupted by one or more heteroatoms selected from sulfur, nitrogen, and oxygen, preferably oxygen. A halogen atom suitably denotes a fluorine, chlorine or bromine atom.

The invention also relates to compounds of formula I in which R¹ represents a straight-chained or branched C₁₋₁₀ alkyl, in particular a branched C₃₋₁₀ alkyl group, a C₃₋₈ cycloalkyl, a C₃₋₈ cycloalkyl-C₁₋₆ alkyl, C₁₋₁₀ alkoxy-C₁₋₆ alkyl, a C₂₋₁₀ alkenyl, in particular a C₃₋₆ alk-2-enyl group, or a phenyl group being optionally substituted by one to three halogen atoms or C₁₋₁₀ alkyl or C₁₋₁₀ alkoxy groups.

The invention especially relates to compounds of formula I in which R² represents a hydrogen atom or a C₁₋₁₀ alkyl group, in particular a hydrogen atom.

When R¹ is an optionally substituted C₃₋₈ cycloalkyl group, preferably a cyclopropyl, cyclopentyl or cyclohexyl group, R² preferably represents a hydrogen atom.

When R¹ is a C₃₋₆ alk-2-enyl group, preferably an allyl or 2-methylallyl group, R² preferably represents a hydrogen atom or a C₁₋₃ alkyl group.

The invention further relates to compounds of formula I in which R¹ and R² together with the interjacent nitrogen atom form an optionally substituted heterocyclic ring, preferably an optionally substituted C₃₋₇ heterocyclic ring in which one CH₂ group may be replaced by O or S, in particular a pyrollidine, piperidine, tetrahydropyridine, in particular 1,2,3,6-tetrahydropyridine, morpholine, thiomorpholine, azepane or azocane ring which is optionally substituted by one or more C₁₋₁₀ alkyl, in particular methyl, groups.

Included in the scope of the present invention are (R) and (S) isomers and atropisomers of compounds of formula I having an chiral center and the racemates thereof, and salts, N-oxides and acid addition compounds.

The compounds according to formula I include oils, gums, or, predominantly, crystalline solid materials. They are especially useful due to their valuable fungicidal properties, in particular their enhanced systemicity and enhanced fungitoxicity against rice diseases and powdery mildews compound to known fungicidal compounds. For example, they can be used in agriculture or related fields for the control of phytopathogenic fungi such as Altemaia solani, Botrytis cinerea, Cercospora beticola, Cladosporium herbarum, Corticium rolfsii, Erysiphe graminis, Guignardia bidwellii, Helminthosporium tritici repentis, Leptosphaeda nodorum, Magnaporthe gdsea f. sp. oryzae. Micronectriella nivalis, Monilinia fructigena, Mycosphaerella ligulicola, Mycosphaerella pinodes, Phomopsis viticola, Pseudopeziza tracheiphila, Phytophthora infestans, Puccinia recondita, Pyrenophora teres, Pyricularia grisea fsp. oryzae, Rhizoctonia solani, Venturia inaequalis, Uncinula necator and Sclerotinia scierotiorum, in particular for the control of Altemaria solani, Botrytis cinerea and Rhizoctonia solani. The compounds of general formula I according to the invention possess a high fungicidal activity within a wide concentration range and may be used in agriculture without any difficulties.

Moreover, the compounds according to the invention show enhanced residual control of fungi, in particular of grape powdery mildew compared with conventional fungicides.

Good results in terms of control of phythopathogenic fungi are obtained with a compound as defined in formula I wherein:

Hal represents a chloro atom, and

R² represents a hydrogen atom or a C₁₋₃ alkyl group.

Especially good results in terms of control of phytopathogenic fungi are obtained by using, for example, the following compounds of formula I:

5-chloro-7-(N-ethyl-N-2-methylallylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(azocan-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(4-methylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine, 5-chloro-7-(thiomorpholin4-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(azepan-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-bicyclo[2.2. 1 ]heptan-2-yl-amino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(piperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(2,4-dimethylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine, 5-chloro-7-(N-1,2,2-trimethylpropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-cyclopentylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(2-methylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(3-methylpiperidin-1-yl)-6-(2,3,6 -trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-cyclohexylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-cycloheptylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-allyl-N-ethylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-3-chloropropyl-N-methylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-2-methylpropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(4-isopropylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine, 5-chloro-7-(2-methylpyrollidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-[N-(2,² -dichlorocyclopropyl)-methyl-N-methylamino]-6 (2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine, 5-chloro-7-(N-but-2-yl-amino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-cyclopropylmethyl-N-propylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-methyl-N-2-methylpropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-butyl-N-ethyllamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N,N-di-ethylamino) -6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-isopropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine, 5-chloro-7-(3,3-dimethylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-cyclopropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-cyclohexyl-N-methylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(1,4-diazepan-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-allyl-N-hexylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-[4-(1-formylamino-2,2,2-trichloroethyl)-piperazin-1-yl]-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 5-chloro-7-(N-allyl-N-cyclopentylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine.

The present invention further provides a process for the preparation of a compound of formula I as defined above which comprises

reacting a compound of the formula II ##STR6## in which Hal is as defined for formula I;

with an amine of the formula III ##STR7## in which R¹ and R² are as defined for formula I,

to produce a compound of formula I.

Compounds of formula II are novel and may be prepared by known techniques, for example, according to EP 0 770 615, by reacting 3-amino-1,2,4-triazole with 2-(2,3,6-trifluorophenyl)-substituted malonic acid ester of formula IV, ##STR8## wherein R represents alkyl, preferably C₁₋₆ alkyl, in particular methyl or ethyl, under alkaline conditions, preferably using high boiling tertiary amines as for example tri-n-butylamine.

The resulting 5,7-dihydroxy-6-(2,3,6-trifluorophenyl)-triazolopyrimidine is subsequently treated with a halogenating agent, preferably with a brominating or chlorinating agent, such as phosphorus oxybromide or phosphorus oxychloride, neat or in the presence of a solvent. The reaction is suitably carried out at a temperature in the range from 0° C. to 150° C., the preferred reaction temperature being from 80° C. to 125° C.

The malonates of formula IV can be prepared by treating commercially available alkyl 2,3,6-trifluorobenzoate, in particular ethyl 2,3,6-trifluorophenylacetate with dialkylcarboxylates, in particular diethylcarboxylate in the presence of a base, especially an alkali alkoxide such as sodium ethoxide.

Accordingly, the invention relates to the novel intermediates of formula II, in particular 5,7-dichloro-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, to the malonates of formula IV, and to the novel 5,7-dihydroxy-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo-[1,5-a]pyrimidine.

The reaction between the 5,7-dihalo-6-(2,3,6-trifluorophenyl)-triazolopyrimidines of formula II and the amine of formula III is preferably carried out in the presence of a solvent. Suitable solvents include ethers, such as dioxane, diethyl ether and, especially, tetrahydrofuran, halogenated hydrocarbons such as dichloromethane and aromatic hydrocarbons, for example toluene. The reaction is suitably carried out at a temperature in the range from 0° C. to 70° C., the preferred reaction temperature being from 10° C. to 35° C. It is also preferred that the reaction is carried out in the presence of a base. Suitable bases include tertiary amines, such as triethylamine, and inorganic bases, such as potassium carbonate or sodium carbonate. Alternatively, an excess of the compound of formula III may serve as a base.

Due to excellent activity, the compounds of formula I may be used in cultivation of all plants where infection by phytopathogenic fungi is not desired, e.g. cereals, solanaceous crops, vegetables, legumes, apples, vine.

The invention encompasses a fungicidal composition which comprises an active ingredient, which is at least one compound of formula I as defined above, and one or more carriers. A method of making such a composition is also provided which comprises bringing a compound of formula I as defined above into association with the carrier(s). Such a composition may contain a single active ingredient or a mixture of several active ingredients of the present invention. It is also envisaged that different isomers or mixtures of isomers may have different levels or spectra of activity and thus compositions may comprise individual isomers or mixtures of isomers.

A composition according to the invention preferably contains from 0.5% to 95% by weight (w/w) of active ingredient.

A carrier in a composition according to the invention is any material with which the active ingredient is formulated to facilitate application to the locus to be treated, which may for example be a plant, seed, soil, or water in which a plant grows, or to facilitate storage, transport or handling. A carrier may be a solid or a liquid, including material which is normally a gas but which has been compressed to form a liquid.

The compositions may be manufactured into e.g. emulsion or emulsifiable concentrates, solutions, oil in water emulsions, wettable powders, soluble powders, suspension concentrates, dusts, granules, water dispersible granules, micro-capsules, gels, aerosols, tablets and other formulation types by well-established procedures. These procedures include intensive mixing and/or milling of the active ingredients with other substances, such as fillers, solvents, solid carriers, surface active compounds (surfactants), and optionally solid and/or liquid auxiliaries and/or adjuvants. The form of application such as spraying, atomizing, dispersing or pouring may be chosen like the compositions according to the desired objectives and the given circumstances.

Solvents may be aromatic hydrocarbons, e.g. Solvesso® 200, substituted naphthalenes, phthalic acid esters, such as dibutyl or dioctyl phthalate, aliphatic hydrocarbons, e.g. cyclohexane or paraffins, alcohols and glycols as well as their ethers and esters, e.g. ethanol, ethyleneglycol mono- and dimethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, or γ-butyrolactone, higher alkyl pyrrolidones, e.g. n-octylpyrrolidone or cyclohexylpyrrolidone, epoxidized plant oil esters, e.g. methylated coconut or soybean oil ester and water. Mixtures of different liquids are often suitable.

Solid carriers, which may be used for dusts, wettable powders, water dispersible granules, or granules, may be mineral fillers, such as calcite, talc, kaolin, montmorillonite or attapulgite. The physical properties may be improved by addition of highly dispersed silica gel or polymers. Carriers for granules may be porous material, e.g. pumice, kaolin, sepiolite, bentonite; non-sorptive carriers may be calcite or sand. Additionally, a multitude of pre-granulated inorganic or organic materials may be used, such as dolomite or crushed plant residues.

Pesticidal compositions are often formulated and transported in a concentrated form which is subsequently diluted by the user before application. The presence of small amounts of a carrier which is a surfactant facilitates this process of dilution. Thus, preferably at least one carrier in a composition according to the invention is a surfactant. For example, the composition may contain at two or more carriers, at least one of which is a surfactant.

Surfactants may be nonionic, anionic, cationic or zwitterionic substances with good dispersing, emulsifying and wetting properties, and mixtures thereof.

Wettable powders suitably may contain 5 to 90% w/w of active ingredient and, in addition, a solid inert carrier, 3 to 10% w/w of dispersing and wetting agents and, where necessary, 0 to 10% w/w of stabilizer(s) and/or other additives such as penetrants or stickers. Dusts may be formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant, and may be diluted in the field with further solid carrier to give a composition usually containing 0.5 to 10% w/w of active ingredient. Water dispersible granules and granules may have a size between 0.15 mm and 2.0 mm and may be manufactured by a variety of techniques. Generally, these types of granules will contain 0.5 to 90% w/w active ingredient and 0 to 20% w/w of additives such as stabilizer, surfactants, slow release modifiers and binding agents. Emulsifiable concentrates of this invention suitably may contain, in addition to a solvent or a mixture of solvents, 1 to 80% w/v active ingredient, 2 to 20% w/v emulsifiers and 0 to 20% w/v of other additives such as stabilizers, penetrants and corrosion inhibitors. Suspension concentrates may be milled so as to obtain a stable, non-sedimenting flowable product and suitably contain 5 to 75% w/v active ingredient, 0.5 to 15% w/v of dispersing agents, 0.1 to 10% w/v of suspending agents such as protective colloids and thixotropic agents, 0 to 10% w/v of other additives such as defoamers, corrosion inhibitors, stabilizers, penetrants and stickers, and water or an organic liquid in which the active ingredient is substantially insoluble; certain organic solids or inorganic salts may be present dissolved in the formulation to assist in preventing sedimentation and crystalization or as antifreeze agents.

Aqueous dispersions and emulsions, for example compositions obtained by diluting the formulated product according to the invention with water, also lie within the scope of the invention.

Of particular interest in enhancing the duration of the protective activity of the compounds of this invention is the use of a carrier which will provide slow release of the pesticidal compounds into the environment of a plant which is to be protected.

The biological activity of the active ingredient can also be increased by including an adjuvant in the spray dilution. An adjuvant is defined here as a substance which can increase the biological activity of an active ingredient but is not itself significantly biologically active. The adjuvant can either be included in the formulation as a coformulant or carrier, or can be added to the spray tank together with the formulation containing the active ingredient.

As a commodity, the compositions preferably may be in a concentrated form, whereas the end user generally employs diluted compositions. The compositions may be diluted to a concentration down to 0.001% of active ingredient. The doses usually are in the range from 0.01 to 10 kg a.i./ha.

Examples of formulations according to the invention are:

    ______________________________________                                         Emulsion                                                                         Concentrate (EC)                                                               Active Ingredient Compound of Example 2 30% (w/v)                              Emulsifier(s) Atlox ® 4856 B/Atlox ® 4858 B.sup.1) 5% (w/v)                                           (mixture containing calcium alkyl aryl                                         sulfonate, fatty alcohol ethoxylates and         light aromatics/mixture containing                                             calcium alkyl aryl sulfonate, fatty                                            alcohol ethoxylates and light aromatics)                                      Solvent Shellsol ® A.sup.2) to 1000 ml                                      (mixture of C.sub.9 -C.sub.10                                                  aromatic hydrocarbons)                                                        Suspension                                                                     Concentrate (SC)                                                               Active Ingredient Compound of Example 2 50% (w/v)                              Dispersing agent Soprophor ® FL.sup.3) 3% (w/v)                             (polyoxyethylene polyaryl phenyl ether                                         phosphate amine salt)                                                         Antifoaming Rhodorsil ® 422.sup.3) 0.2%                                    agent (nonionic aqueous emulsion of (w/v)                                       polydimethylsiloxanes)                                                        Structure agent Kelzan ® S.sup.4) 0.2%                                      (Xanthan gum) (w/v)                                                           Antifreezing Propylene glycol 5% (w/v)                                         agent                                                                          Biocidal agent Proxel ®.sup.5) 0.1%                                         (aqueous dipropylene glycol solution (w/v)                                     containing 20%                                                                 1,2-benisothiazolin-3-one)                                                    Water  to 1000 ml                                                              Wettable Powder                                                                (WP)                                                                           Active Ingredient Compound of Example 2 60% (w/w)                              Wetting agent Atlox ® 4995.sup.1) 2% (w/w)                                  (polyoxyethylene alkyl ether)                                                 Dispersing agent Witcosperse ® D-60.sup.6) 3% (w/w)                         (mixture of sodium salts of condensed                                          naphthalene sulfonic acid and                                                  alkylarylpolyoxy acetates                                                     Carrier/Filler Kaolin 35% (w/w)                                                Water Dispersible                                                              Granules (WG)                                                                  Active Ingredient Compound of Example 2 50% (w/w)                              Dispersing/ Witcosperse ® D-450.sup.6) 8% (w/w)                            Binding agent (mixture of sodium salts of condensed                             naphthalene sulfonic acid and alkyl                                            sulfonates)                                                                   Wetting agent Morwet ® EFW.sup.6) 2% (w/w)                                  (formaldehyde condensation product)                                           Antifoaming Rhodorsil ® EP 6703.sup.3) 1% (w/w)                            agent (encapsulated silicone)                                                  Disintegrant Agrimer ® ATF.sup.7) 2% (w/w)                                  (cross-linked homopolymer of                                                   N-vinyl-2-pyrrolidone)                                                        Carrier/Filler Kaolin 35% (w/w)                                              ______________________________________                                          .sup.1) commercially available from ICI Surfactants                            .sup.2) commercially available from Deutsche Shell AG                          .sup.3) commercially available from RhonePoulenc                               .sup.4) commercially available from Kelco Co.                                  .sup.5) commercially available from Zeneca                                     .sup.6) commercially available from Witco                                      .sup.7) commercially available from International Speciality Products    

The compositions of this invention can also comprise other compounds having biological activity, e.g. compounds having similar or complementary pesticidal activity or compounds having plant growth regulating, fungicidal or insecticidal activity. These mixtures of pesticides can have a broader spectrum of activity than the compound of formula I alone. Furthermore, the other pesticide can have a synergistic effect on the pesticidal activity of the compound of formula I.

The other fungicidal compound can be, for example, one which is also capable of combating diseases of cereals (e.g. wheat) such as those caused by Erysiphe, Puccinia, Septoda, Gibberella and Helminthosporium spp., seed and soil borne diseases and downy and powdery mildews on vines, early and late blight on solanaceous crops, and powdery mildew and scab on apples etc. These mixtures of fungicides can have a broader spectrum of activity than the compound of formula I alone. Furthermore, the other fungicide can have a synergistic effect on the fungicidal activities of the compound of formula I.

Examples of the other fungicidal compounds are anilazine, azoxystrobin, benalaxyl, benomyl, bethoxazin, binapacryl, bitertanol, blasticidin S, Bordeaux mixture, bromuconazole, bupirimate, captafol, captan, carbendazim, carboxin, carpropamid, chlorbenzthiazon, chlorothalonil, chlozolinate, copper-containing compounds such as copper oxychloride, and copper sulfate, cycloheximide, cymoxanil, cypofuram, cyproconazole, cyprodinil, dichlofluanid, dichlone, dichloran, diclobutrazol, diclocymet, diclomezine, diethofencarb, difenoconazole, diflumetorim, dimethirimol, dimethomorph, diniconazole, dinocap, ditalimfos, dithianon, dodemorph, dodine, edifenphos, epoxiconazole, etaconazole, ethirimol, etridiazole, famoxadone, fenapanil, fenarimol, fenbuconazole, fenfuram, fenhexamid, fenpiclonil, fenpropidin, fenpropimorph, fentin, fentin acetate, fentin hydroxide, ferimzone, fluazinam, fludioxonil, flumetover, fluquinconazole, flusilazole, flusulfamide, flutolanil, flutriafol, folpet, fosetylaluminium, fuberidazole, furalaxyl, furametpyr, guazatine, hexaconazole, imazalil, iminoctadine, ipconazole, iprodione, isoprothiolane, kasugamycin, kitazin P, kresoxim-methyl, mancozeb, maneb, mepanipyrim, mepronil, metalaxyl, metconazole, methfuroxam, myclobutanil, neoasozin, nickel dimethyldithiocarbamate, nitrothalisopropyl, nuarimol, ofurace, organo mercury compounds, oxadixyl, oxycarboxin, penconazole, pencycuron, phenazineoxide, phthalide, polyoxin D, polyram, probenazole, prochloraz, procymidione, propamocarb, propiconazole, propineb, pyrazophos, pyrifenox, pyrimethanil, pyroquilon, pyroxyfur, quinomethionate, quinoxyfen, quintozene, spiroxamine, SSF-126, SSF-129, streptomycin, sulfur, tebuconazole, tecloftalame, tecnazene, tetraconazole, thiabendazole, thifluzamide, thiophanate-methyl, thiram, tolclofosmethyl, tolylfluanid, triadimefon, triadimenol, triazbutil, triazoxide, tricyclazole, tridemorph, triflumizole, triforine, triticonazole, validamycin A, vinclozolin, XRD-563, zarilamid, zineb, and ziram.

In addition, the formulations according to the invention may contain at least one compound of formula I and any of the following classes of biological control agents such as viruses, bacteria, nematodes, fungi, and other microorganisms which are suitable to control insects, weeds or plant diseases or to induce host resistance in the plants. Examples of such biological control agents are: Bacillus thuringiensis, Verticllium lecanii, Autographica califomica NPV, Beauvaria bassiana, Ampelomyces quisqualis, Bacilis subtilis, Pseudomonas chlororaphis, Pseudomonas fluorescens, Steptomyces griseovifidis and Trichoderna harzianum.

Moreover, the formulations according to the invention may contain at least one compound of formula I and a chemical agent that induces the systemic acquired resistance in plants, such as nicotinic acid or derivatives thereof, 2,2-dichloro-3,3-dimethyl-cyclopropylcarboxylic acid or BION.

The compounds of formula I can be mixed with soil, peat or other rooting media for the protection of the plants against seed-borne, soilborne or foliar fungal diseases.

The invention also includes the fungicidal use of a compound of formula I as defined above, or a composition as defined above, and a method for combating fungus at a locus, which comprises treating the locus (which may be for example plants subject to or subjected to fungal attack seeds of such plants or the medium in which such plants are growing or are to be grown) with such a compound or composition.

The present invention is of wide applicability in the protection of crop and ornamental plants against fungal attack. Typical crops which may be protected include vines, grain crops such as wheat and barley, rice, sugar beet, top fruit, peanuts, potatoes, vegetables and tomatoes. The duration of the protection is normally dependent on the individual compound selected, and also a variety of external factors, such as climate, whose impact is normally mitigated by the use of a suitable formulation.

The following examples further illustrate the present invention. It should be understood, however, that the invention is not limited solely to the particular examples given below.

EXAMPLE 1 Preparation of 5-Chloro-6-(2,3,6-trifluorophenyl)-7-(4-methylpiperid-1-yl)-1,2,4-triazolo[1.5a]pyrimidine

1A 5,7-Dihydroxy-6-(2,3,6-trifluorophenyl)-7-(4-methylpiperid-1-yl)-1,2,4-triazolo[1.5a]pyrimidine

A mixture of diethyl (2,3,6-trifluorophenyl)-malonate (167.5 g, 0.58 moles; obtained from ethyl (2,3,6-trifluorophenyl)-acetate and diethyl-carbonate in the presence of sodium ethoxide), 3-amino-1,2,4-triazole (48.5 g, 0.58 moles), tributylamine (151 ml, 0.635 moles) and mesitylene (304 ml) is heated at 160° C. for 28 hours, cooled to room temperature and decanted to obtain an oily residue. The residue is diluted with aqueous sodium hydroxide (100ml, 10%). The mesitylene phase is added and the aqueous mixture is extracted with diethyl ether (850 ml). The aqueous phase is added to concentrated hydrochloric acid (360 ml). The precipitate formed is colected washed with water and dried to give 102 g of 1A, which is used in the following step without further purification.

1B 5,7-Dichlor-6-(2,3,6-trifluorophenyl)-7-(4-methylpiperid-1-yl)-1,2,4-triazolo[1.5a]pyrimidine

A mixture of 1A (51 g, 0.18 moles), and phosphorous oxychloride (250 ml) is heated in an autoclave at 140° C. and 4 bar for 4 hours. The resultant mixture is cooled to room temperature and is poured in a mixture of dichloromethane and water (600 ml, 1:1). The organic phase is separated, dried and concentrated in vacuo to yield 21.2 g (18.4%) of crude 1B, which is used in the following step without further purification.

1C 5-Chloro-6-(2,3,6-trifluorophenyl)-7-(4-methylpiperid-1-yl)-1,2,4-triazolo[1.5a]pyrimidine

A mixture of 4-methylpiperidine (0.31 g, 3.1 mmoles), triethylamine (0.31 g, 3.1 mmol) and dichloromethane (10 ml) is added to a mixture of 1B (1.0 g, 3.1 mmoles) and dichloromethane (30 ml) under stirring. The reaction mixture is stirred 16 hours at room temperature, subsequently washed two times with dilute hydrochloric acid (5%) and once with water. The organic layer is separated, dried with anhydrous sodium sulphate and the solvent is evaporated under reduced pressure. Treatment of the resulting light brown oil with ethyl acetate(50 ml) yields 0.45 g a white powder (38%) having a melting point of 156-157° C.

EXAMPLES 2-60

The following examples (Table I; structure and melting point) are synthesized analogously to Example 1.

                  TABLE 1                                                          ______________________________________                                           #STR9##                                                                         -                                 melting                                     Example R.sup.1 R.sup.2 point (° C.)                                  ______________________________________                                         2       2-methylallyl   ethyl      84-85                                       3       --(CH.sub.2).sub.7 --  144-145                                           4 --(CH.sub.2).sub.2 --S--(CH.sub.2).sub.2 -- 109                              5 --(CH.sub.2).sub.6 -- 187-190                                              6       bicyclo[2.2.1]hept-2-yl                                                                        H          179                                         7       --(CH.sub.2).sub.5 --  165-167                                           8 --CH(CH.sub.3)--CH.sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.2 -- 137-138       9       1,2,2-trimethylpropyl                                                                          H          124                                           10 cyclopentyl H 139-141                                                     11      --CH(CH.sub.3)--(CH.sub.2).sub.4 --                                                                   131-133                                           12 --CH.sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.3 -- 127-130                    13      cyclohexyl      H          164-165                                       14 cycloheptyl H 142-143                                                       15 allyl ethyl 90-92                                                           16 3-chloropropyl methyl 112-113                                               17 2-methylpropyl H 158-160                                                  18      --(CH.sub.2).sub.2 --CH(isopropyl)-(CH.sub.2).sub.2 --                                                151-152                                           19 --CH(CH.sub.3)--(CH.sub.2).sub.4 -- 157-161                               20      (2,2,-dichlorocyclopropyl)-                                                                    methyl     80-81                                          methyl                                                                        21 1-methylpropyl H 68-70                                                      22 cyclopropylmethyl propyl 126-127                                            23 2-methylpropyl methyl 139-141                                               24 butyl ethyl  73                                                             25 ethyl ethyl 147-149                                                         26 isopropyl H 127                                                           27      --CH.sub.2 --C(CH.sub.3).sub.2 --(CH.sub.2).sub.3 --                                                  83-84                                           28      cyclopropyl     H          183-184                                       29 cyclohexyl methyl 128-129                                                 30      --(CH.sub.2).sub.2 --NH--(CH.sub.2).sub.3 --                                                          >300                                            31      allyl           hexyl      oil                                         32      --(CH.sub.2).sub.2 --N(R*)--(CH.sub.2).sub.2 --                                                       140                                             33      cyclopropyl     allyl      119-120                                     ______________________________________                                          R*: 2,2,2trichloro-1-formylaminoethyl                                    

Biological Investigations

A. Determination of Minimum Inhibitory Concentration by Test Compounds in the Serial Dilution Test with Various Phytopathogenic Fungi

The MIC (Minimum Inhibitory Concentration) value, which indicates the lowest concentration of the active ingredient in the growth medium which causes a total inhibition of myecelial growth, is determined by serial dilution tests using Microtiter plates with 24 or 48 wells per plate. The dilution of the test compounds in the nutrient solution and the distribution to the wells is carried out by a TECAN RSP 5000 Robotic Sample Processor. The following test compound concentrations are used: 0.05, 0.10, 0.20, 0.39, 0.78, 1.56, 3.13, 6.25, 12.50, 25.00, 50.00 and 100.00 mg/mi. For preparation of the nutrient solution, V8 vegetable juice (333 ml) is mixed with calcium carbonate (4.95 g), centrifuged, the supernatant (200 ml) diluted with water (800 ml) and autoclaved at 121° C. for 30 min.

The respective inocula (Altemara solani, ALTESO; Botrytis cinerea, BOTRCI; Magnaporthe gdisea f. sp. Otyzae, PYRIOR; Rhizoctonia solani, RHIZSO;) are added into the wells as spore suspensions (50 ml; 5×10⁵ /ml) or agar slices (6 mm) of an agar culture of the fungus.

After 6-12 days incubation at suitable temperatures (18-25° C.), the MIC values are determined by visual inspection of the plates (Table II; n.t. =not tested).

                  TABLE II                                                         ______________________________________                                         Ex. No.  ALTESO   BOTRCI     PYRIOR RHISZO                                     ______________________________________                                         1        0.1      0.78       n.t.   1.56                                         2 0.04 0.1 0.04 0.1                                                            3 0.04 0.78 n.t. 0.78                                                          4 0.1 50 n.t. 12.5                                                             5 0.2 1.56 n.t. >100                                                           6 0.2 1.56 n.t. >100                                                           7 0.2 0.78 n.t. 0.78                                                           8 0.2 0.39 n.t. >100                                                           9 0.39 1.56 0.2  6.25                                                          10 0.78 1.56 n.t. 6.25                                                         11 0.78 1.56 n.t. 0.78                                                         12 0.78 3.13 n.t. 50                                                           13 0.78 3.13 n.t. >100                                                         14 0.78 3.13 n.t. >100                                                         15 0.78 0.78 0.39 0.39                                                         16 0.78 6.25 n.t. 12.5                                                         17 0.78 6.25 n.t. >100                                                         18 0.78 >100 n.t. >100                                                         19 1.56 0.78 0.2  0.78                                                         20 1.56 12.5 n.t. >100                                                         21 1.56 1.56 n.t. 3.13                                                         22 1.56 1.56 n.t. 0.2                                                          23 3.13 1.56 n.t. 3.13                                                         24 3.13 6.25 1.56 >100                                                         25 6.25 1.56 n.t. 0.78                                                         26 6.25 6.25 n.t. 6.25                                                       ______________________________________                                    

Comparison Tests

The MIC data of the following [1,2,4]triazolo[1,5-a]pyrimidines being substituted in the 6-position by a 2-chloro-6-fluorophenyl group, a 2,6-difluorophenyl group or a 2,3-difluoropheny group which are disclosed in U.S. Pat. No. 5,593,996 have been compared with the corresponding compounds according to this invention which are substituted by a 2,3,6-trifluorophenyl group:

    ______________________________________                                           #STR10##                                                                     Com-                                                                             pound R.sup.1 R.sup.2 X Y origin                                             ______________________________________                                         Example 1                                                                             --(CH.sub.2).sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.2 --                                            F     F   invention                                    Compari- --(CH.sub.2).sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.2 -- F H US                                           5,593,996                                    son A1                                                                         Compari- --(CH.sub.2).sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.2 -- Cl H US                                          5,593,996                                    son A2                                                                         Compari- --(CH.sub.2).sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.2 -- H F US                                           5,593,996                                    son A3                                                                       Example 2                                                                             2-methylallyl                                                                              ethyl      F   F   invention                                  Compari- 2-methylallyl ethyl Cl H US 5,593,996                                 son B1                                                                         Compari- 2-methylallyl ethyl F H US 5,593,996                                  son B2                                                                         Example cyclopentyl H F F invention                                            10                                                                             Compari- cyclopentyl H Cl H US 5,593,996                                       son C1                                                                         Compari- cyclopentyl H H F US 5,593,996                                        son C2                                                                       ______________________________________                                    

The obtained MIC values are shown in the following table III:

                  TABLE III                                                        ______________________________________                                         Compound   ALTESO      BOTRCI   RHISZO                                         ______________________________________                                         Example 1  0.1         0.78     1.56                                             Comparison A1 0.04 1.56 3.13                                                   Comparison A2 0.1 0.78 25                                                      Comparison A3 >100 >100 >100                                                   Example 2 0.04 0.1 0.1                                                         Comparison B1 0.39 0.2 0.78                                                    Comparison B2 0.39 0.1 0.39                                                    Example 10 0.78 1.56 6.25                                                      Comparison C1 0.78 1.56 25                                                     Comparison C2 1.56 6.25 >100                                                 ______________________________________                                     

What is claimed is:
 1. A compound of formula I ##STR11## in which R¹ and R² each independently represent a hydrogen atom or an C₁ -C₁₀ alkyl, C₂ -C₁₀ alkenyl, C₂ -C₁₀ alkynyl, C₃ -C₁₀ alkadienyl, C₁ -C₁₀ haloalkyl, C₆ or C₁₀ aryl, C₆ or C₁₀ heteroaryl containing at least one nitrogen, oxygen or sulfur ring atom, C₃ -C₈ cycloalkyl, C₅ -C₁₀ bicycloalkyl, pyrrolodinyl, pyrrazolidin, piperidinyl, piperazinyl, morpholin-4-yl or thiomorpholin-4-yl group, which group optionally may be substituted by one or more halogen atoms or nitro, cyano, hydroxy, C₁₋₆ alkyl, C₃₋₆ cycloalkyl, C₃₋₆ cyloalkenyl, C₁₋₆ haloalkyl, C₃₋₆ halocycloalkyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, tri-C₁₋₄ alkylsilyl, pheny, halo- or dihalo-phenyl or pyridyl groups, orR¹ and R² together with the interjacent nitrogen atom represent a C₃₋₇ heterocyclic ring in which one CH₂ group may be replaced by O or S, which ring optionally may be substituted by one or more C₁₋₁₀ alkyl groups, and Hal represents a halogen atom.
 2. A compound according to claim 1 in whichR¹ represents straight chained C₁ -C₆ -alkyl, straight chained or branched C₂ -C₆ -alkenyl, C₃ -C₈ cycloalkyl or C₅ -C₉ bicyclealkyl and R² represents hydrogen or C₁ -C₆ -alkyl, or R¹ and R² together with the interjacent nitrogen atom represent a heterocyclic ring having four to seven carbon atoms and optionally one or two non-adjacent nitrogen, oxygen or sulfur atoms being optionally substituted with one or two C₁ -C₆ -alkyl groups.
 3. A compound according to claim 2 in which R² represents a hydrogen atom or C₁ -C₃ -alkyl group.
 4. A compound according to claim 2 in which R¹ and R² together with the interjacent nitrogen atom represent a heterocyclic ring comprising 4 to 7 carbon atoms and optionally 1 sulfur atom being optionally substituted by one or two methyl group.
 5. A compound according to claim 1, selected from the group 2 consisting of:5-chloro-7-(N-ethyl-N-2-methylallylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(azocan-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine; 5-chloro-7-(4-methylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(thiomorpholin-4-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(azepan-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine; 5-chloro-7-(N-bicyclo[2.2.1 ]heptan-2-ylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(piperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine; 5-chloro-7-(2,4-dimethylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-1,2,2-trimethylpropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-cyclopentylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(2-methylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(3-methylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-cyclohexylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-cycloheptylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-allyl-N-ethylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-3-chloropropyl-N-methylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-2-methylpropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(4-isopropylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(2-methylpyrollidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-[N-(2,2-dichlorocyclopropyl)-methyl-N-methylamino]-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-but-2-ylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]-pyrimidine; 5-chloro-7-(N-cyclopropylmethyl-N-propylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-methyl-N-2-methylpropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-butyl-N-ethyllamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N,N-di-ethylamino) -6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-isopropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(3,3-dimethylpiperidin-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-cyclopropylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-cyclohexyl-N-methylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(1,4-diazepan-1-yl)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-(N-allyl-N-hexylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; 5-chloro-7-[4-(1-formylamino-2,2,2-trichloroethyl)-piperazin-1-yl]-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine; and, 5-chloro-7-(N-allyl-N-cyclopentylamino)-6-(2,3,6-trifluorophenyl)-[1,2,4]triazolo[1,5-a]pyrimidine.
 6. A process for the preparation of a compound of formula I, as defined in claim 1, which comprises reacting a compound of formula II ##STR12## in which Hal is as defined in claim 1, with an amine of the formula III ##STR13## in which R¹ and R² are as defined in claim 1, optionally in the presence of a base.
 7. A fungicidal composition which comprises a carrier, and as active agent, at least one compound of formula I as defined in claim
 1. 8. A method of combating fungus at a locus which comprises treating the locus with a fungicidally effective amount of a compound of formula I as defined in claim
 1. 9. A method of combating fungus at a locus which comprises treating the locus with a fungicidally effective amount of a composition as defined in claim
 7. 